Ethylene polymerization with catalyst of group va metal oxide and alkaline earth hydride



Uni ed trainer 2,773,053 .Patented Dec, 4, 1956 ice p z 1 I ranges of temperature and pressure. The practice of 2,773,053 the p e ntpro s an ead to gr aseike ethy ene hom E'IZHYLENE POLYMERIZATION WITH CATALYST GROUP VA EARTH HYDRlDE v a Edmund Field, Chicago, and Morris Feller, Park Forest, -Ill., assignors -to Standard Oil Company, Chicago, Il l.,

acorporationoflndiana t l No Drawin Application July .22, 1953,- I p senaliumsmzs l V 115 Claims. erase-44hr This invention relates to anovel process for the polymerization of ethylene inthe presence of alkaline earth polymershav'ing an approximate molecular weight range of 300 to 00, Wax-like ethylene homopolyrnershaving an approximate specific viscosity gx 10 between about 1000, and 10,000 and tough, resinous ethylene homo.-

" polymers having an approximate specific viscosity X of "10,000 to more than 300,000 (1; relative- :1) X1 0 1. Bythe term ftough; resinous polyethylene as-used herein wemean polymer 'hayinga brittle point below "-5 0" (A. SQI. Mf-MethodD746- 51T), impact strength great,-

' er than two foot pounds'per inch of notch '(ATSI T. M,

the polymerizationof ethylene to high molecular Weight normally solid polymers. Still another object of our invention'is to provide a novel process for the-conversion of gas mixtures comprising essentially ethylene to high molecular weight sol-id resinous or plasticrna-terial-s.

I A furtheraobjectisto provide a relatively low temperature, low pressure process for the conversion of ethylene" containing gases to high molecular weight resinous or plastic materials. An additional objectof the present invention is to providea process for the oopolyr-ne'rization of ethylene with other'polymerizable mate-rials, par

ticularly with. a normally gaseous .monoolefin such as propylene, to provide novel resinous materials. f These and'other objects of our invention will become apparent fromthe ensuing descriptionthereof.

Briefly, the inventive process "comprises the convers'ion;

of ethylene principally :to high molecular weigh-t normal-1 1y solid, resinous polymers and to grease like polymers lay-contact with calcium hydride and vanadia or other Group VA metal oxide, preferably supported on a diffic-ultly reducible metal oxide such asactiyated alumina,

titania, zirconia, silica, clays, and the 'like. Barter-all of the-calcium hydride may he replacedbythe hydrides of Be, Mg, SrandBa. The inventive process is eflected art-temperatures between about '75- ;C. and about "325 16., Pr ferably be ween about 130 and 2620 ;C., andpres sures between about atmospheric and -l5';000ep. s. 'i.:g.-or

i h rhpre erably between about 20.0mm 5:00am about 000 .8 ig- 'lT'he normally iSOlid materials produced byithecatalytic ,eonvension tend to accumulate upon and withinthe solid catalyst. It :is desirable .to supply to.

the reaction zone a liquid medium which serves ibnth: as .a reaction medium and a Solvent for the solid, reaction products. Suitable liquid reaction media ifor polymerization include various hydrocarbons, particularly an taromatic hy s on such a benzene, tolu ene .orxylenes. The conversiontof ethylenecan be :efliected in theabsence of atliquid reaction medium or sQlvent and the catalyst containing accumulated solid polymeric conyersion prod ucts :canv'be treated from to time, 'within or out-1 properties, dependent upon the selection of operating The inventive process -is characterized 'by; extreme flexibility both .as regards operating conditions conditions.

and as ;regards the products producible thereby, Thus thevpresentsprocess canabe efieeted overext-remely broad' Method D256-47T'Izodmachine) and minimum elongation'at room temperature (253 of 100%.

polymerizable materials, particularly with propylene, or

other mono-olefinig hydrocarbons such as" n-butyl,enes, isobutyleiie t butylethylene; acetylene, butadiene, iso

preneg 'aiid the like,'-usual-ly in-proportions between about 1 andalaout 25% o Weight, basedon the weight :of ethylene. c p 3' 0 Calcium hydride isan a-r-ticleof commerce andjcan be prepared -by a va-r'iety of methods.- Thusgmetallic calcium reacts readily -w;ith hydrogen at 400- C. to produce calcium hydride. Calcium hydride can also be'pr'epared 'by the reaction of-QaC with magnesium and hydro gen, which produces calcium "hydride containing Mg'O. Strontiumhydride can be pre'pared by the reaction of-a strontium 'lialide-with-[lithium aluminum hydride (A. n; Fin'holt e1 31,,3. Amnfilheml Soc. =69, 1199-1203 1947) Bariumhydride can beprepared by thesame. methods as areusedzfor the preparation (if-calcium and strontium by drides. Beryllium and magnesiumhydri'des can 'be'j prepared Fbyspecia'l methods rknownin the art. BTW ill be understood that thespecific preparative methods involved form no part of our invention and that any method Which-yields the desired metahhydrid'e can be employed. Usually vthe "hydridesuemployed according to the present inyention are prepared 'ontsideithe reactor, but theymay beipreparedin situ and polymerization can then beeffectedinthe reaetort. I

lik tit-Auction or it uctionsrof'tt-he metal hydride in our Process aremot ,well -understood. Thus,.fcalcium hydride aeatgalyst for the polymerization of ethylene l lat Weight, normally solid polymers under {t '2; cqndit ns deserihedherein. Yettcalcium hydride vcp-tunctions somehow with the 'v-anadia catalyst to inc ease the p oductivi y (p ymer yiel of i catalyse I I3 epe t o calci mhyd e or other alkaline earthqmetal hydr d employed in our orocesis a z aried fro wahou 0-0 11 ab u or merchan 's zb-Y weight. pe t by w ig t of su srqup 5 me a oxide. muslin a. wei h -a raid atal-y tl u al y et-ween abcu h l a ab u 1.0- igh h ptimum proiibntiq s can r ad ly be; determin d n pe s in tan es, by simpte smal -scal t sts wit e sp ifi eedt to ks, liquid reaction rnedium, reaction medium: catalyst ratio, catal. mn ratu e, pres and na ur o t errtod st wh ch ,i ldelsi' ed- U al y, th -meta hydrid is em loy in ,prono tiqnslbetw eaa out and a ou .2 part y wei h pe mi by weightht va adia na al-ra r ot er ox de cata yst at ratio be wee about 5 and abou 3000 o s .9! m re ofliqu d e ct e umlpehpa t y sh 9f ranadiaatalys 1 V Y "The relative propo t ns of support to the catalytic metal x d no i r npal and m y be var d th ou out a rel ti e y wide n e such that each omr' e is pr g n js of a ilea t approxima e y 1 weight. percent; "The usualmetai oxide; support ratios ,are in, the rangeof about 12040151, or approximately 1:10

We may employ conditioned alumina-metal oxide catalyst composed of gamma-alumina base containing about 1 to 80%, preferably about 5 to 35%, or approximately of vanadia or otherlGroup, VA catalytic metal oxide supported thereon.

Gamma-alumina, titania and zirconia supports for our catalysts may be prepared in any known manner and the oxides of vanadium or. other Group VA metal may likewise be incorporated in, or deposited on, the base in any known manner. The Group VA metal oxide may be incorporated in the catalyst base in any known manner, e. g. by impregnation, coprecipitation, co-gelling, and/ or absorption, and the catalyst base and/or finished catalystmay be heat stabilized in the known manners. Cobalt, calcium, magnesium, copper and zinc salts of vanadic acid may also be employed upon a diificultly reducible metal oxide support and are preferably treated with hydrogen under conditions to effect partial reduction thereof before use in our process. I I 1 The vanadia or other Group VA metal oxide catalyst is subjected to a reducing or conditioning treatment before use in the polymerization process. The conditioning or reducing treatment is preferably effected with hydrogen although other reducing agents such as carbon monoxide, mixtures of hydrogen and carbon monoxide (water gas, synthesis gas, etc.), sulfur dioxide, hydrogen sulfide, dehydrogenatable hydrocarbons, etc., may be employed. Hydrogen can be employed as a reducing agent at temperatures between about 250 C. and about 850 C., although it is more often employed at temperatures within the range of 450 C. to 650C. The hydrogen partial pressure in the reduction or conditioning operation may, be varied from subatmospheric pressures, for example even 0.1 pound (absolute), to relatively high pressures up to 3000 p. s. i. g., or even more. The simplest reducing operation may be effectedjwith hydrogen atabout atmospheric pressure.

The partial reduction of the metal oxide catalyst in' which the metal is present in its pentavalent state can be effected in the presence of the metal hydride promoter, prior to contacting the combination of catalysts with ethylene. We have at times observed that an induction period before ethylene polymerization can be eliminated or substantially reduced by pressuring hydrogen into-the reactor containing the solvent, ethylene, metal oxide catalyst and metal hydride promoter, e. g. at hydrogen pressures between about 10 and about 900 p. s. i. g., preferably 100-400 p. s. i. g.; under these conditions only a small proportion of the ethylene is reduced to ethane.

Lithium aluminum hydride, an exceptionally active reducing agent, conditions and activates catalysts containing pentavalent sub-group 5 metal oxides even at temperatures as low as 35 C., although in general temperatures between about 100 and about 300 C. canbe employed. In practice, the catalyst is treated with a suspension of LiAlH4 in a liquid hydrocarbon'at weight ratios of about 0.2 to about 1 LiA1H4 to solid catalyst. Sodium hydride (or sodium plus H2) is effective in the reducing and conditioning treatment at temperatures above about 180 C. and may be employed in the same proportions as LiA1H4. employed to effect some reduction of VzOs supported on gamma-alumina at 230 C. and higher temperatures The conditioning treatment hereinabove described desirable not only for fresh catalyst, but is also required for catalyst which has become relatively inactive in the polymerization step. As will be hereinafter described; the polymer formed in the polymerization reaction must be continuously or intermittently removed from the catalyst particles, preferably by means of solvents, and it is usually necessary or desirable to condition a catalyst surface which has been thus freed to some extent from polymer before it is again employed for effecting polymeriza-- tion. When catalyst can no longer be rendered sufficient Calcium hydride may also be ly active by simple removal of polymer and conditioning with a reducing gas as hereinabove described, it may be regenerated by extraction with water, ammonium salts or dilute aqueous acids, thereafter burning combustible deposits therefrom with oxygen followed by the conditioning step. Detoxification of the catalysts by treatment with dilute aqueous solutions of per-acids such as permolybdic, pervanadic or pertungstic acids may be practiced, followed by hydrogen-conditioning of the catalysts.

The catalyst can be employed in various forms and sizes, e. g., as powder, granules, microspheres, broken filter cake, lumps, or shaped pellets. A convenient form in which the catalysts may be employed is as granules of about -100 mesh/inch size range.

The charging stock to the present polymerization process preferably comprises essentially ethylene. The ethylene charging stocks may contain inert hydrocarbons, as

r in refinery gas streams, for example, methane, ethane,

propane, etc. However, it is preferred to employ as pure and concentrated ethylene charging stocks as it is possible to obtain. When the charging stock contains propylene as well as ethylene, both these olefins may contribute to the production of resinous high molecular weight products. The molar ratio of ethylene to propylene may be varied over the range of about 0.1 to about 20. The charging stock may contain other components such as small amounts of hydrogen and it may contain other polymerizable materials such as butylene, acetylene, t-butylethylene, etc.

It is desirable to minimize or avoid the introduction of oxygen, carbon dioxide, water or sulfur compounds into contact with the catalyst.

In general, polymerization can be effected in the present process at temperatures between about 75 and about 325 C. Increasing the polymerization temperature tends to reduce the average molecular weight and density of the polymer produced by the process. Usually polymerization is effected in the present process at temperatures between about 110 and about 275 C. or the preferred narrower range of about 220 to about 260 C. The conjoint use of polymerization temperatures between about 230 and about 250 C. and a liquid hydrocarbon reaction medium such as benzene, xylenes, decalin, or methyldecalins is highly desirable in producing ethylene polymers having specific viscosities (X10 ranging on the average from about 10,000 to about 30,000.

It has been found that the present process can be employed for the production of relatively high molecular weight ethylene polymers at relatively low pressures. The process of the present invention may be eflFected to some extent even at atmospheric pressure. The upper limit of polymerization pressure is dictated by economic considerations and equipment limitations and may be 10,000

p. s. i. g., 20,000 p. s. i. g., or even more. A generally useful and economically desirable polymerization pres sure range is between about 200 and about 5000 p. s. i. g.,

preferably between about 500 and about 1500 p. s. i. g.,

general, this variable is'readily adjustable to obtain thedesired results. In operations in which the olefin charg ing stock is caused to flow continuously into and out of contact with the solid catalyst, suitable liquid hourly space velocities are usually selected between about 0.1 and about 10 volumes, preferably about 0.5 to 5 or about 2 volumes of olefin solution in a liquid reaction medium, which is usually an aromatic hydrocarbon such as benzene, xylenes, or. tetralin, or a cycloaliphatic hydrocarbon, such as decalin (decahydronaphthalene).

The amount of ethylene in such solution may be in the range of about 2, to 50% by weight, preferably about 2 to about weight percent or, for example, about 5 to 10 weight percent. When the ethylene concentration in the liquid reaction medium is decreased below about 2 weight percent, the molecular weight and melt viscosity of the polymeric products tend to drop sharply. In general, the rate of ethylene polymerization tends to increase with increasing concentration of the ethylene in the liquid reaction medium. However, the rate of ethylene polymerization to form high molecular weight, normally solid polymers is preferably not such as to yield said solid polymers in quantities which substantially exceed the solubility thereof in said liquid reaction medium under the reaction conditions, usually up to about 5-7 weight percent, exclusive of the amounts of polymeric products which are selectively adsorbed by the catalyst. Although ethylene concentrations above 10 weight percent in the liquid reaction medium may be used, solutions of ethylene polymer above 510% in the reaction medium become very viscous and difficult to handle and severe cracking or spalling of the solid metal oxide catalyst particles or fragments may occur, resulting in catalyst carry-over'as fines with the solution of polymerization products and extensive loss of catalyst from the reactor.

In batch operations, operating periods of between onehalf and about 20 hours are employed and the reaction autoclave is charged with ethyleneas the pressure falls as a result of the olefin conversion reaction.

The solvent: catalyst weight ratio can be varied in the range of about 5 to about 3000, or even higher for flow systems. The employment of high solvent: catalyst ratios, which is rendered possible by thepresence of a metal hydride, is very important in obtaining substantial yields of polymer. a

The olefin charging stocks can be polymerized in the gas phase and in the absence of a liquid reaction medium by contact with the metal hydrides and metal oxide catalysts. Upon completion of the desired polymerization reaction it is then possible to treat the solid catalyst for the recovery of the solid polymerization products, for example by extraction with suitable solvents. However, in the interests of obtaining increased rates of olefin conversion and of continuously removing solid conversion products from the catalyst, it is much preferred to effect the conversion of the olefin in the presence of suitable liquid reaction media. The liquid reaction medium may also be employed as a means of contacting the olefin with catalyst by preparing a solution of the olefin feed stockin the liquid reaction medium and contacting the resultant solution with the polymerization catalyst.

The liquid reaction medium functions as a solvent to remove some of the normally solid product from the catalyst surface.

Various classes of hydrocarbons or their mixtures which.

are liquid and substantially inert under the polymerization conditions of the present process can be employed. Members of the aromatic hydrocarbon series, particularly the mononuclear aromatic hydrocarbons, viz., benzene,.

ing operations as distillates orbottoms, from cycle stock fractions of crackingoperations, etc.

We may also employ certain alkyl naphthalenes which are liquid under the polymerization reaction conditions, for example, l-methylnaphthalenc, Z-isopropylnaphthalene, l-n-amylnaphthalene and the like, or commercially producedfractions containing these hydrocarbons.

Certain classes of aliphatic hydrocarbons can also be employed .as a liquid hydrocarbon. reaction medium in the present process. Thus, we may'employ various satu-v rated hydrocarbons (alkanes and cycloalkanes) which are liquid under the polymerization reaction conditions and which do not crack substantially under the reaction con ditions. Either pure alkanesv or cycloalkanes or commercially available mixtures, freed of catalyst poisons, may be employed. For example, we may employ straight run naphthas or kerosenes containing alkanes and cycloalkanes. Specifically, we may employ liquid or liquefied alkanes such as n-pentane, n-hexane, 2,3-dirnethylbutane, n-octane, iso-octane (2,2,4-trimethylpentane), n-decane, ndodecane, cyclohexane, methylcyclohexane, dimethylcyclopentane, ethylcyclohexane, decalin, methyldecalins, dimethyldecalins and the like.

We may also employ a liquid hydrocarbon reaction medium comprising liquid olefins, e. g., n-hexenes, cyclo hexene, octanes, hexadecenes andthe like. i

The normally solid polymerization products which are retained on the catalystsurface or grease-like ethylene polymers may themselves function to some extent .as -a.

liquefied hydrocarbon reaction medium, but it is highly desirable to add a viscosity-reducing hydrocarbon, such as those mentioned above, thereto in the reaction zone. The liquid hydrocarbon reaction medium should be freed of poisons before use inthe present invention by acid treatment, e. g., with anhydrous p-toluenesulfonic acid, sulfuric acid, or by equivalent treatments, for example with aluminum halides, or other Friedel-Crafts catalysts, maleic anhydride, calcium, calcium hydride, sodium or other alkali metals, alkali metal hydrides, lithium aluminum hydride, hydrogen and hydrogenation catalyst (hydrofining), filtration through a column of copper grains or 8th group metal, etc, or by combinations ofsuch treatments.

Wehave purified C. P. xylenes by refluxing with a mixture of 8 weight percent MoO3-AI2O3 catalyst and LiA1H4 (50 cc. xylenel g. catalyst-O.2 g. LiAlH4) at atmospheric pressure, followed 'by distillation of the xylencs. Still more effective purification of solvent can be achieved by heating it to about 225 -250 C. with either sodium and hydrogen or NaH plus an -8 weight percent molybdena-alumina in a pressure vessel.

Temperature control during the course of the ethylene conversion process can be readily accomplished owing tothe presence in the reaction zone of a large liquid mass having relatively high heat capacity. The liquid hydro-1 carbon reaction medium can be cooled by heat exchange inside or outside the reaction zone.

When solvents such as xylenes are employed, some slight alkylation thereof by ethylene can occur under the reaction conditions. The alkylate is removed with grease in the present process, can be separated therefrom by fi'actional distillation and can, if desired, be returned to the polymerization zone.

The methods of polymerization an'd equipment described in our application 'for United States Letters Patent, Serial No. 524,607 may be employed without substantial change in employing the present catalyst.

The following are nonlimitative examples of our invention. Melt viscosity was determined at 145 C. by

the method of Dienes and Klemm, J. Appl. Phys. 17,

Example 1 The reactor was a 250 cc. stainless steel pressure vessel provided with a magnetically-actuated stirring :device which was reciprocated within the reaction zone. The catalyst was 10 wt. percent V205 supported upon gammaalumina, 30-100 mesh, prereduced before use with hydrogen at 350 C. and atmospheric pressure for '16 hours. The reactor was charged with cc. of dehydrated and deoxygenatedtxylenes, 51g. of the prereducedjvanadia catalyst and 2 g. of calcium hydride, while excludingain:

After pressure testing-the reactor with hydrogen, the con- 7 tents were heated to 260 C. and then pressured with ethylene to 820 p. s. i. An ethylene pressure drop of about 405 p. s. i. was noted in 8.5 hours. The reaction yielded 91 weight percent, based on the weight of vanadia catalyst, of a solid polymer having a specific viscosity of 16,600, melt viscosity of 1.9 10 and density of 0.9852 (24 0.), together with 6 weight percent of grease-like ethylene polymer and 17 weight percent of xylenes alkylate.

Example 2 The 250 cc. reactor was charged with 100 cc. of purified toluene, 1 g. of calcium hydride and 2 g. of NbzOs supported on silica gel which was prereduced with molecular hydrogen for 16 hours at 400 C. and atmospheric pressure. The reactor contents were heated at 204 C. under a blanket of hydrogen and ethylene was then introduced to a partial pressure of about 850 p. s. i. Over the course of the 19.5-hour reaction period, the temperature was raised to 232 C. The total yield of ethylene polymer obtained in the reaction was 2.12 grams per gram of catalyst.

Example 3 The procedure of Example 1 is repeated but an equal weight of barium hydride is substituted for calcium hy-. dride in the reactor charge. The solid ethylene polymer is separated and worked up as before.

Example 5 The procedure of Example 2 is repeated but an equal weight of strontium hydride is substituted for calcium hydride and the solid ethylene polymer is separated and worked up as before.

Example 6 The procedure of Example 1 is repeated but an equal weight of magnesiumhydride is substituted for calcium hydride to produce a solid ethylene polymer.

Example '7 i The procedure of Example 3 is repeated but beryllium hydride is substituted in equal weight for calcium hydride to produce a solid ethylene polymer.

. When an alkaline earth metal hydride is employed alone under reaction conditions which yield solid ethylene polymers by the process of the present invention, no solid polyethylene can be produced. Thus no ethylene pressure drop was observed, nor any solid polyethylenes, in an attempted reaction in which the reactor was charged with 50 cc. of purified toluene, 2 grams of calcium hydride and 300 p. s. i. ethylene (at 25 C.) and the mixture was heated with stirring to 355 C. Similarly, the Group VA metal oxide catalyst alone is ineffective for the production of polyethylene under our reaction conditions, as shown by the following experiment:

The 250 cc. reactor was charged with 100 cc. of purified toluene and 10 grams of 10 weight percent V205 on gamma-alumina which was prereduced by treatment with molecular hydrogen at 350 C. and atmospheric pressure for 16 hours. The mixture was heated with stirring under a blanket of hydrogen to 202 C. and ethylene was then injected to a partial pressure of 845 p. s. i. No

solid polyethylene was produced in this attempted re-'- 8 tion can be subjected to such after-treatment as may be desired, to fit them for particular uses or to impart desired properties. Thus, the polymers can be extruded, mechanically milled, filmed or cast, or converted to sponges or latices. Antioxidants, stabilizers, fillers, extenders, plasticizers, pigments, insecticides, fungicides, etc. can be incorporated in the polyethylenes and/or in by product alkylates or greases. The polyethylenes may be employed as coating materials, binders, etc. to even a wider extent than polyethylenes made by prior processes.

The polymers produced by the process of the present invention, especially the polymers having high specific viscosities, can be blended with the lower molecular weight polyethylenes to impart stiffness or flexibility or other desired properties thereto. The solid resinous products produced by the process of the present invention can, like? wise, be blended in any desired proportions With hydrocarbon oils, waxes such as paraflin or petrolatum'waxes, with ester waxes, with high molecular weight polybutylcues, and with other organic materials. Small proportions between about .01 and about 1 percent of the various polymers of ethylene produced by the process of the present invention can be dissolved or dispersed in hydrocarbon lubricating oils to increase V. I. and to decrease oil consumption when the compounded oils are employed in motors; larger amounts of polyethylenes may be compounded with oils of various kinds and forv various purposes. r

The products having a molecular weight of 50,000 or more produced by the present invention, can be employed in small proportions to substantially increase the viscosity of fluent liquid hydrocarbon oils and as gelling agents for such oils. The solution of about 1 gram of an ethylene polymer having a specific viscosity 10 of about 50,000 in about one liter of xylenes at a temperature close to the boiling point produces an extremely viscous solution.

, The polymers produced by the present process can be subjected to chemical modifying treatments, such as halogenation, halogenation followed by dehalogenation, sulfohalogenation by treatment with sulfuryl chloride, sulfonation, and other reactions to which hydrocarbons may be subjected.

This application is a continuation-in-part of our application for United States Letters Patent, Serial No. 324,607, filed December 6, 1952, and now U. S. Patent No. 2,731,452. r

Having thus'described our invention, what we claim is:

1.' In a process for the production of a polymer having a molecular weight of at least about 300, the steps of contacting ethylene at a reaction temperature between about C. and about 325 C. with an alkaline earth metal hydride and a catalyst prepared by treating a Group VA metal pentoxide. supported upon a difficultly reducible metal oxide with a reducing gas at a temperature between about 350 C. and about 850 C. to produce a catalyst containing a lower-valent Group VA metal oxide, and separating a polymer having a molecular weight of at least about 300 thus produced.

2. In a process for the production of a normally solid, resinous hydrocarbon material, the steps of contacting ethylene at a temperature between about 75 C. and about 325 C. in the presence of a liquid hydrocarbon reaction medium with an alkaline earth metal hydride and a catalyst prepared by treating a Group VA metal pentoxide supported upon a diflicultly reducible metal oxide with hydrogen at a temperature between about 350 C. and about 850 C. to produce a catalyst containing a lower-valent Group VA metal oxide, and separating a normally solid, resinous hydrocarbon material thus produced.

3. The process of claim 2 wherein said Group VA metal pentoxide is V205 and said difi'icultly reducible metal oxide is an activated alumina.

pentoxide is NbzOs.

5. The process of claim 2 wherein said Group VA metal pentoxide is Ta205.

6. The process of claim 2 wherein said alkaline earth metal hydride is calcium hydride.

7. The process of claim 2 wherein said alkaline earth metal hydride is barium hydride.

8. The process of claim 2 wherein said alkaline earth metal hydride is strontium hydride.

9. The process of claim 2 wherein said alkaline earth metal hydride is magnesium hydride.

10'. The process of claim 2 wherein said alkaline earth metal hydride is beryllium hydride.

11. In a process for the production of a normally solid, resinous hydrocarbon material, the steps of contacting ethylene in the presence of a liquid hydrocarbon reaction .medium at an effective polymerization temperature beproduce a catalyst containing a lower-valent vanadium oxide, and separating a normally solid, resinous hydrocarbon material thus produced.

12. The process of claim 11 wherein said liquid hydrocarbon reaction medium is a monocyclic aromatic hydrocarbon. 7

13. In a process for the production of a normally solid, high molecular weight ethylene polymer, the steps which comprise contacting ethylene in a concentration between about 2 weight percent and about 10 weight percent in a liquid hydrocarbon reaction medium at a reaction temperature between 130 C. and about 260 C. and a reaction pressure between about 200 and about 5000 p. s. i. g. with calcium hydride and a catalyst prepared by treating V205 supported upon a diflicultly reducible metal oxide 7 with hydrogen at a temperature between about 350 C. and about 850 C. to produce a catalyst containing a lower-valent vanadium oxide, the ratio of said calcium hydride to said vanadium oxide catalyst being between about 0.01 and about 10 by weight, and separating a normally solid, high molecular weight ethylene polymer thus produced.

14. The process of claim 13 wherein the reaction medium is a xylene.

15. The process of claim 13 wherein said difficultly reducible metal oxide is gamma-alumina.

No references cited. 

1. IN A PROCESS FOR THE PRODUCTION OF A POLYMER HAVING A MOLECULAR WEIGHT OF AT LEAST ABOUT 300, THE STEPS OF CONTACTING ETHYLENE AT A REACTION TEMPERATURE BETWEEN ABOUT 75* C. AND ABOUT 325* C. WITH AN ALKALINE EARTH METAL HYDRIDE AND A CATALYST PREPARED BY TREATING A GROUP VA METAL PENTOXIDE SUPPORTED UPON A DIFFICULTLY REDUCIBLE METAL OXIDE WITH A REDUCING GAS AT A TEMPERATURE BETWEEN ABOUT 350* C. AND ABOUT 850* C. TO PRODUCE A CATALYST CONTAINING A LOWER-VALENT GROUP VA METAL OXIDE, AND SEPARATING A POLYMER HAVING A MOLECULAR WEIGHT OF AT LEAST ABOUT 300 THUS PRODUCED. 